问题补充：
It is recognized that the part the UN plays in international relations is important.
A. in which
B. where
C. that
D. of which
答案：
A. in which
B. where
(答案→)C. that
D. of which
解析：考查定语从句。the part是先行词，play a part in在......中扮演角色，定语从句缺少宾语，用that/which引导定语从句；A、B作状语，D作定语，相当于whose，排除A、B、D。故选C。
